The invention relates to fuel delivery systems for automobiles, and more specifically to fuel pump delivery systems for use with multi-chambered or multiple fuel tanks.
The use of multi-chambered fuel tanks or multiple fuel tanks in a vehicle is known. For example, the use of a bifurcated fuel tank, also commonly referred to as a saddle tank, in conjunction with fuel delivery systems having a single fuel pump is known. In such systems, a reservoir surrounds the fuel pump and is constantly filled to insure that a steady supply of fuel is available to the pump at all times. Normally, fuel is drawn into the fuel pump from the bifurcated tank portion housing the fuel pump, but if the fuel level is low or vehicle maneuvering is such that the fuel pump inlet cannot draw fuel, the fuel pump instantly draws fuel from the reservoir. A jet pump is used to draw fuel through a crossover line from the opposing bifurcated portion of the tank and pump the fuel into the reservoir. The reservoir is usually overflowing and excess fuel fills the bifurcated tank portion housing the fuel pump. This insures that if fuel remains in either of the bifurcated tank portions, it is available to the fuel pump.
The reservoir, fuel pump, jet pump, and crossover line are typically packaged with additional components in a standard fuel pump module that can be quickly and easily installed in the tank as a single unit.
Today""s high-performance and high-power automobiles require a higher rate of fuel flow to the engine than can often be provided with a single standard capacity fuel pump used with multiple fuel tanks or in a multi-chambered fuel tank. There are numerous ways to obtain the higher fuel flow capacity. One possibility is to replace the standard capacity fuel pump with a high performance, high capacity fuel pump. This modification is problematic in that a high capacity fuel pump is larger than a standard capacity fuel pump and will not fit properly in the reservoir of a standard fuel pump module. Using a larger fuel pump requires designing, manufacturing, and assembling new fuel pump module components, including a new reservoir, to accommodate the larger fuel pump. Modifications to the fuel tank may also be needed. The tooling and testing costs for such modifications are high.
Another possibility for obtaining the higher fuel flow capacity is to use two standard capacity fuel pumps in a single fuel pump module. This possibility would also require changing the fuel pump module components to accommodate the two standard capacity fuel pumps. Again, modifications to the tank may also be required.
The present invention overcomes the problems described above by incorporating two standard fuel pump modules for multiple tanks or in a multi-chambered tank. In the preferred embodiment, one standard fuel pump module is used in each portion of a bifurcated fuel tank to provide the necessary fuel delivery to the engine. The use of standard fuel pump modules substantially eliminates the costs associated with any new tooling and testing that would otherwise be required to modify the fuel pumping capacity of a single standard fuel pump module.
Using a standard fuel pump module in each portion of the bifurcated fuel tank presents some challenges not previously encountered when using a single fuel pump module in one side of the bifurcated tank. Since the engine demands fuel flow from both fuel pumps, it is important that both fuel pumps have access to a sufficient amount of fuel. Due to automobile maneuvering (wherein fuel sloshes over the bifurcating wall of the tank), partial tank filling, and variations in fuel pump flow capacities, the fuel levels in the bifurcated portions are often unequal. Using a fuel pump in each portion of the bifurcated fuel tank therefore mandates a method of insuring that fuel is available to both fuel pumps at all times.
In the present invention, the standard fuel pump modules are equipped with reservoirs and jet pumps that can compensate for the differences in the fuel levels of a bifurcated tank. Each jet pump has its own dedicated crossover fuel line that transfers fuel over the bifurcating wall. The first crossover fuel line communicates with the first jet pump and is dedicated to transferring fuel from the second bifurcated portion to the reservoir in the first bifurcated portion. The second crossover fuel line communicates with the second jet pump and is dedicated to transferring fuel from the first bifurcated portion to the reservoir in the second bifurcated portion.
At a minimum, each jet pump transfers fuel at a sufficient rate to insure that both fuel pumps can meet the fuel consumption demands of the engine. More preferably, each jet pump transfers fuel at a higher rate than is necessary to fulfill the demand on the fuel pumps. Therefore, both jet pumps and crossover lines, working independently of one another, help to equalize the fuel level in the bifurcated portions of the tank as the tank empties, thereby insuring that both fuel pumps have sufficient access to fuel. While described in conjunction with bifurcated fuel tanks, the present invention could also be used with other types of multi-chambered tanks or with multiple fuel tanks.
The dual fuel pump module system of the present invention is an alternative to the system described in co-pending U.S. patent application Ser. No. 09/498,313. In that application, a single crossover fuel line communicates with both jet pumps. Shuttle valves control the direction of fuel flow through the single crossover line to maintain substantially equal fuel levels in both bifurcated portions until the tank is empty. Should one bifurcated portion empty before the other, both jet pumps draw fuel from the bifurcated portion with the remaining fuel, thereby insuring that both fuel pumps continue to provide fuel to the engine until both bifurcated portions are substantially empty.
The dual fuel pump module system of the present invention provides a reliable, alternative method of delivering fuel from both tank portions of a bifurcated fuel tank to the engine. The present invention allows for the use of standard components and fuel tank platforms in fuel systems having higher fuel demands.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.